Dengue: biology, diagnosis and pathology

Published on June 30, 2020   27 min

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Hello, my name is Duane Gubler. I'm a professor emeritus at the Duke-NUS Medical School in Singapore. I have a long career in dengue. I've been working on dengue for nearly 50 years. I spent 25 years at the Centers for Disease Control and Prevention prior to going to Hawaii and to Singapore. I was the founding director of the CDC dengue branch in Puerto Rico.
Today I'm going to be talking about dengue and tell you everything you want to know about dengue. I'll begin by talking very briefly about the biology and transmission cycle. Then also briefly talk about the clinical presentations and diagnosis, a bit about pathogenesis, and then focus on the changing epidemiology that we're seeing in the past 30-40 years and finish by talking about prevention and control.
The dengue viruses belong to the family flaviviridae, the genus Flavivirus. As you can see from this first slide, there are a number of flaviviruses but the groups that we're interested in are the tick-borne and the mosquito-bornes. The dengue viruses belong to the mosquito-borne viruses. You can see them up in the right-hand corner there, very closely related to Zika and Spondweni virus and also through the Culex flaviviruses that includes Japanese encephalitis and West Nile.
There are four serotypes- antigenic types- of dengue viruses. We call them dengue 1, 2, 3 and 4. They're antigenically distinct, but they're really considered one virus. A fifth serotype has recently been described from Malaysia. It's not documented that it is a fifth serotype yet that's why I have a question mark by it. It's very closely related to dengue type 4. So we're not sure if it's a variant of dengue 4 or whether it's a serotype. The dengue viruses, like all flaviviruses, have an open reading frame. There are 10 proteins that make up that reading frame, three structural proteins and seven non-structural proteins. All of these play an important role in the biology of the dengue viruses.